This invention relates to a device and method for removing from a well light non-aqueous liquids that float on the surface of water in the well, and is particularly concerned with a simple inexpensive device having no moving parts that can passively remove crude oil and other hydrocarbons from groundwater wells.
It is not uncommon for light hydrocarbons, such as crude oil, gasoline and other distillate products, to escape into the environment from oil producing fields, service stations, refineries, natural gas processing plants and other related petroleum processing facilities. Quite frequently these light hydrocarbons work themselves into the soil where they migrate downwardly and end up collecting on the surface of the water table. These hydrocarbons float on the water surface, spread across the water in the direction of least resistance and partially dissolve into the water causing significant pollution. Thus, most state and local governments have laws and regulations requiring the removal of these hydrocarbons from groundwater wells. As an example, the state of Alaska requires the removal of crude oil and other non-aqueous liquids from groundwater monitoring or observation wells in the Swanson River oil and gas field. This requirement applies to even very small amounts of non-aqueous liquids found in these monitoring wells.
Although there are established methods for removing and recovering light non-aqueous liquids such as hydrocarbons from water wells, these methods normally involve the use of relatively complicated downwell devices having moving parts to remove and recover rather large amounts of liquids or the use of expensive surface equipment to pull vacuums in the wells. Such devices and equipment tend to be either somewhat complicated and expensive or difficult to use. Thus, there exists a need for a relatively simple device without moving parts that is inexpensive to fabricate and can be easily used to passively remove relatively small amounts of hydrocarbons and other light non-aqueous liquids from the surface of water in monitoring and other wells.